This invention relates to a novel Ziegler type supported catalytic component for .alpha.-olefin polymerization which is of highly uniform particle diameter, of good fluidity, not readily disintegrating and has a high degree of polymerizing activity, high stereospecific polymer productivity and high bulk density (hereinafter will be called the catalytic component for short unless otherwise specified) and to a method of carrying out homo- or co-polymerization (hereinafter will be called (co-) polymerization) of an .alpha.-olefin in the presence of a catalyst composition consisting of the above stated catalytic component and an organo-aluminum compound.
More particularly, the invention relates to a catalytic component for .alpha.-olefin polymerization prepared by treating, with alcohol and/or phenol, a solid product obtained by allowing an organo-magnesium compound or a mixture of an organo-magnesium compound and an organo-aluminum compound or their reaction product to react, in the presence of an electron donor and an .alpha.-olefin, with a mixture of a halogenating agent other than a halogenated titanium compound and a titanium compound or their reaction product or by further treating the treated matter with a halogenated titanium compound. The invention also relates to a method for (co-) polymerization of an .alpha.-olefin which is carried out either in the presence of a catalyst composition consisting of the catalytic component thus obtained and an organo-aluminum compound or with use of a concomitant electron donor compound together with the catalyst composition.
An important feature of the present invention resides in that the weight of the polymer product obtainable in accordance with the invention is large per unit weight of the catalytic component and titanium atoms, that is, the catalytic component has a high degree of polymerizing activity. Other important features include that: The insufficient bulk density and the insufficient stereospecific polymer productivity which have represented the shortcomings of the conventional carrier catalytic components of the Ziegler type can be substantially improved. Besides, both the invented catalytic component and the polymer obtained therefrom are in a spherical particle shape and are of highly homogeneous particle diameter to result in good fluidity.
Generally, the catalysts which have been used for the manufacture of stereospecific .alpha.-olefin polymers are of the type known by the name of a Ziegler-Natta catalyst consisting of a transition metal belonging to the groups IV-VI of the periodic table and an organo-metallic compound of a metal belonging to the groups I-III of the periodic table.
Catalytic components that have been employed in the industrial manufacture of .alpha.-olefin polymers such as propylene, butene-1, etc. include an .alpha.-olefin polymerizing catalytic component comprising a titanium trichloride composition as a compound of the transition metal belonging to the groups IV-VI of the periodic table or a magnesium-containing halide which is used as carrier to have titanium tetra-chloride carried thereby; and an .alpha.-olefin polymerizing catalytic component in which titanium tetra-chloride is supported by a carrier obtained by pulverizing a magnesium-containing halide together with an electron donor compound or the like.
Further, recent Japanese patent application laying open publications relative to .alpha.-olefin polymerizing supported catalytic components of the Ziegler type to which the present invention also relates include Japanese Patent Application Laid-Open No. 55-58207 and Japanese Patent Application Laid-Open No. 55-133408. The Japanese Patent Application Laid-Open No. 55-58207 discloses an .alpha.-olefin polymerizing catalytic component in which a solid product obtained by allowing an organo-magnesium compound to react with a halogenating agent other than a halogenated titanium compound is treated with an electron donor compound not containing active hydrogen and with another electron donor compound containing active hydrogen; and then the product thus treated is further treated with a halogenated titanium compound. Another Japanese Patent Application Laid-Open No. 55-133408 discloses an olefin (co-) polymerizing method in which a three-component catalyst composition consisting of an .alpha.-olefin polymerizing catalytic component, an organo-metallic compound and a Lewis base is used; and the .alpha.-olefin polymerizing catalytic component is obtained by treating a solid organo-magnesium compound with an aromatic alcohol and a Lewis base and by further treating the treated product with a titanium compound and a vanadium compound. In accordance with these methods of prior art, however, the polymerizing activity and stereospecific polymer productivity of the catalyst are still low. Besides, the bulk density of the polymer obtainable therefrom is also unsatisfactorily low. Accordingly, in the .alpha.-olefin polymer thus obtained, there remains a considerable amount of residual catalyst, which presents various problems in terms of the stability, workability, etc. of the .alpha.-olefin polymer. These problems then necessitates provision of some additional facilities for the removal of the residual catalyst and the stabilization of the polymer. In addition to these problems, the low productivity for a stereospecific polymer necessitates provision of some further facility for extraction and removal of atactic polypropylene which is produced as by-product. This requires a great amount of energy. Further, since the bulk density of the polymer produced is low, the polymer is very difficult to handle in carrying out a molding process, etc. It is a further shortcoming of the .alpha.-olefin polymer obtained by using the .alpha.-olefin polymerizing catalytic component that the particles of the polymer do not show sufficient resistance to disintegration during processes such as transfer by pumping, centrifugal separation and the like that follow the polymerization. The polymer particles readily disintegrate and tend to produce fine powder or amorphous particles. Besides, the catalytic component itself also does not have much resistance to disintegration. These shortcomings can be improved by a higher degree of polymerizing activity which can be expressed by the weight of the .alpha.-olefin polymer produced per unit weight of the catalytic component; a higher degree of stereospecific polymer productivity; a higher bulk density of the polymer produced; and a greater resistance to disintegration of the catalyst. Such improvements when would obviate the necessity of the facilities for removal of the above stated residual catalyst and for extraction and removal of the atactic polypropylene and thus would permit reduction in the production cost required in the manufacture of an .alpha. -olefin polymer.
The present inventors, therefore, strenuously conducted studies for obtaining an .alpha.-olefin polymerizing catalytic component that has a higher degree of polymerizing activity than the above stated prior art .alpha.-olefin polymerizing catalytic component and would give an .alpha.-olefin polymer which is of excellent stereospecificity, of high bulk density, of spherical particle shape and does not readily disintegrate. These studies have led to the present invention which is based on the following finding that: An .alpha.-olefin polymerizing catalytic component obtained by treating, with an alcohol and/or phenol, a solid product which is obtained by allowing an organo-magnesium compound or a mixture of an organo-magnesium compound and an organo-aluminum compound or their reaction product to react, in the presence of an electron donor compound and an .alpha.-olefin, with a mixture of a halogenating agent other than a halogenated titanium compound and a titanium compound or their reaction product, or by further treating the treated matter thus obtained with a halogenated titanium compound has a high degree of polymerizing activity for the polymerization of an .alpha.-olefin; has a high degree of stereospecificity; and gives a polymer which is of a high bulk density, spherical in morphology and has sufficient resistance to disintegration.